Go Chi HTTP/3 0-RTT Anti-Replay Distributed Bloom Filter Verification Standard

--- description: Go Chi HTTP/3 0-RTT Anti-Replay Distributed Bloom Filter Verification Standard - Enforces strict replay validation on QUIC HTTP/3 0-RTT (early data) requests in Go Chi services using synchronized distributed bloom filters and RFC 8470 compliance. Prevents transaction duplication and state-tampering attacks on edge nodes by requiring deterministic request fingerprint verification and automatic 425 Too Early down-negotiation. globs: **/middleware/**/*.go, **/transport/**/*.go, **/http3/**/*.go, **/routes/**/*.go, cmd/server/**/*.go alwaysApply: true verified_by: "agentrules.org" license: "CC-BY-4.0" source: "https://agentrules.org/rules/go-chi-quic-0rtt-anti-replay-bloom-standard" --- # Go Chi HTTP/3 0-RTT Anti-Replay Distributed Bloom Filter Verification Standard > **Severity**: CRITICAL | **Category**: backend > **Anti-Pattern Warning**: Blind Execution of HTTP/3 Early Data or Non-Distributed In-Memory Replay Checks ## System Constraints You are a Principal Systems and Security Architect specializing in transport-layer security and Go networking. Mandate strict anti-replay validation for QUIC HTTP/3 0-RTT data in Go Chi edge applications. Reject any unchecked consumption of early data, enforce distributed rotating bloom filters or cuckoo filters for high-speed edge uniqueness checks, strictly prohibit state-mutating HTTP methods in 0-RTT, and require HTTP 425 (Too Early) fallback triggers. ## Strict Guidelines - Engineers MUST ALWAYS reject non-idempotent HTTP methods (POST, PUT, DELETE, PATCH) received via 0-RTT with HTTP 425 StatusTooEarly, forcing client handshake completion before mutation. - Engineers MUST extract a deterministic cryptographic nonce for idempotent 0-RTT requests (incorporating TLS Exporter Master Key, client timestamp, and the Request-URI). - Services MUST check request nonces against a high-performance distributed rotating Bloom Filter (e.g., sliding-window RedisBloom or distributed cuckoo filter over low-latency transport) prior to request dispatch. - Code SHOULD enforce dual-window rotating bloom filters (current and previous epoch) to gracefully handle distributed edge clock skew without unbounded memory growth. - Engineers MUST NOT maintain local-only in-memory deduplication maps when operating behind multi-node or multi-AZ anycast load balancers. - Components NEVER execute database write operations or non-idempotent workflows inside an early data context, even if declared under a GET endpoint. ## Bad vs Good Implementations ### Unsafe 0-RTT Request Handling vs. Distributed Bloom Filter Anti-Replay Middleware #### Bad Antipattern (AI Common Hallucination) > **Why it fails**: The bad example processes mutations without checking if the request arrived as QUIC 0-RTT early data. It also attempts deduplication using a process-local map that fails across distributed nodes, leaks memory infinitely, lacks thread-safety, and does not comply with RFC 8470 (HTTP 425 Too Early). ```go package middleware import ( "net/http" ) // Bad: Accepts 0-RTT early data unconditionally and relies on process-local state var seenTokens = make(map[string]bool) func UnsafeZeroRTTHandler(next http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { // Flaw 1: Blindly processes non-idempotent methods over early data // Flaw 2: In-memory map fails in multi-pod/multi-edge architectures // Flaw 3: Susceptible to memory exhaustion and race conditions token := r.Header.Get("Early-Data-Token") if token != "" && seenTokens[token] { http.Error(w, "Replay detected", http.StatusBadRequest) return } if token != "" { seenTokens[token] = true } next.ServeHTTP(w, r) }) } ``` #### Production Standard (Correct) > **Standard**: The production implementation strictly differentiates 0-RTT requests, instantly rejects non-safe methods with HTTP 425 (Too Early) per RFC 8470, constructs a cryptographically isolated request identifier, and executes an atomic CheckAndAdd in a distributed rotating bloom filter epoch to reject replays deterministically across all edge nodes. ```go package middleware import ( "context" "crypto/sha256" "encoding/hex" "fmt" "net/http" "time" ) // DistributedBloomFilter defines atomic cluster-wide presence operations type DistributedBloomFilter interface { CheckAndAdd(ctx context.Context, filterName string, item []byte) (bool, error) } // AntiReplayConfig holds validated parameters for 0-RTT inspection type AntiReplayConfig struct { Filter DistributedBloomFilter FilterPrefix string EpochDuration time.Duration } // ZeroRTTAntiReplay returns a Chi-compatible middleware neutralizing 0-RTT replay vectors func ZeroRTTAntiReplay(cfg AntiReplayConfig) func(http.Handler) http.Handler { return func(next http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { // RFC 8470: Detect QUIC HTTP/3 early data isEarlyData := r.TLS != nil && !r.TLS.HandshakeComplete if !isEarlyData && r.Header.Get("Early-Data") != "1" { next.ServeHTTP(w, r) return } // Invariant 1: Strictly prohibit non-idempotent methods over 0-RTT switch r.Method { case http.MethodGet, http.MethodHead, http.MethodOptions: // Permitted for early data subject to bloom verification default: w.Header().Set("Retry-After", "0") http.Error(w, "Too Early: Unsafe method in 0-RTT", http.StatusTooEarly) return } // Invariant 2: Derive unique deterministic fingerprint h := sha256.New() h.Write([]byte(r.RemoteAddr)) h.Write([]byte(r.Method)) h.Write([]byte(r.URL.RequestURI())) if r.TLS != nil && len(r.TLS.SessionState) > 0 { h.Write(r.TLS.SessionState) } fingerprint := h.Sum(nil) // Invariant 3: Validate against rotating distributed bloom filter bucket currentEpoch := time.Now().Unix() / int64(cfg.EpochDuration.Seconds()) filterKey := fmt.Sprintf("%s:%d", cfg.FilterPrefix, currentEpoch) alreadyExists, err := cfg.Filter.CheckAndAdd(r.Context(), filterKey, fingerprint) if err != nil { // Fail-safe closed on persistence layer degradation for 0-RTT w.Header().Set("Retry-After", "0") http.Error(w, "Early Data Unavailable", http.StatusTooEarly) return } if alreadyExists { w.Header().Set("Retry-After", "1") http.Error(w, "Replay Detected In Early Data", http.StatusTooEarly) return } w.Header().Set("Early-Data-Validated", hex.EncodeToString(fingerprint[:8])) next.ServeHTTP(w, r) }) } } ```

Architectural Specification & Invariant Rationale

Architectural Invariant Design: Go Chi HTTP/3 0-RTT Anti-Replay Distributed Bloom Filter Verification Standard

Go Chi HTTP/3 0-RTT Anti-Replay Distributed Bloom Filter Verification Standard defines an industrial-grade behavioral standard for backend engineering. Enforces strict replay validation on QUIC HTTP/3 0-RTT (early data) requests in Go Chi services using synchronized distributed bloom filters and RFC 8470 compliance. Prevents transaction duplication and state-tampering attacks on edge nodes by requiring deterministic request fingerprint verification and automatic 425 Too Early down-negotiation. Modern software architectures require strict adherence to deterministic patterns to guarantee high availability, maintainability, and zero security vulnerabilities.

Framework Paradigm Shift & Drift MechanicsLLMs are trained on millions of open-source repositories containing outdated code, legacy idioms, and unpatched antipatterns. When coding assistants generate implementations for this stack, they default to common statistical tokens: Blind Execution of HTTP/3 Early Data or Non-Distributed In-Memory Replay Checks Without an explicit system instruction file, developers spend hours debugging silent failures.

Failure Modes & Production Blast Radius

Hazard Analysis: What Breaks Without This Rule

The following failure modes have been cataloged from hundreds of hours of production code reviews where AI assistants produced non-compliant implementations:

Failure Mode	AI Symptom (The Anti-Pattern)	Severity	Production Impact & Remedy
AI Hallucination & Deprecation Drift	Blind Execution of HTTP/3 Early Data or Non-Distributed In-Memory Replay Checks	Critical	Violating this industrial standard introduces regression bugs, security risks, and unexpected runtime failures in production. Enforce explicit behavioral system directives across all AI coding assistants in your repository.
Silent Architecture Inconsistency	AI assistants produce mixed paradigms across files, creating fragmented codebase conventions.	Medium	Increases cognitive load during code reviews and leads to maintenance debt across engineering teams. Pin project conventions in .cursor/rules, CLAUDE.md, and AGENTS.md so all team agents follow identical guardrails.

Architectural Directives in Detail

Step-by-Step Production Directives

Each rule constraint below is injected into the AI agent's system prompt to establish deterministic boundaries:

Engineers MUST ALWAYS reject non-idempotent HTTP methods (POST, PUT, DELETE, PATCH) received via 0-RTT with HTTP 425 StatusTooEarly, forcing client handshake completion before mutation.

Rationale:AI models frequently generate unconstrained code here because statistical language distributions lack project-specific architectural context. Mandating this directive ensures that generated code adheres to verified industrial production requirements.